Hundreds of homeowners marched through the streets of Shanghai yesterday, demanding refunds on properties they bought in a complex where an unfinished building collapsed late last month. Carrying handwritten signs spelling out their demands, they advanced through Renmin Square, in the heart of the city, chanting: 'Lotus Riverside, refund [our] homes!' The group of close to 300 protesters escalated their campaign into a rare public display of anger after talks with the district government and property developers in the morning failed to produce a result. 'It is very simple, as far as we are concerned: we just want our money back,' said one protester, who would only give her surname, Cao. 'This is the only fair solution. There is no way we can move into those flats or we could get anyone to buy one after what has happened.' The protesters staged a 90-minute sit-in on the steps of the municipal government's headquarters, at times chanting and at one point singing the national anthem. A government negotiator agreed to meet representatives of the group, but protesters later said the outcome was disappointing. 'They said they are creating a channel for communication,' Ms Cao said, 'but it really hasn't solved anything'. The 13-storey building - one of 11 apartment blocks in the Lotus Riverside development - toppled over on its foundations at about 5.30am on June 27. One worker died in the accident, which a government investigation has attributed to excavation work for an underground car park that undermined the foundations, coupled with the weight of a huge pile of waste earth on the other side of the building. The report, released on Friday, said that the collapse was due to the construction company's 'ignorance' and failure to 'consider clearly' the implications of the excavations, but stopped short of apportioning blame. It ruled out design flaws as the cause of the accident, saying building materials and construction methods were in line with regulations. But the investigation immediately came under fire as a government whitewash, particularly as it declared the remaining 10 buildings in the development to be safe and in no danger of collapse. That finding incensed owners of flats in the remaining blocks, who say it hurts their chances of a refund. The government has suggested owners seek redress through the courts, and has provided public lawyers to represent them. However, many protesters rejected the suggestion. 'I don't want this to be decided according to the law,' said one, who asked not to be named. 'There has never been a building that collapsed like this anywhere in the world, never mind just in China, so how can there be a law to deal with that? 'The government allowed them to sell us these homes, so the government should step in to sort it out.' Another protester, who gave her family name as Chen, said the one million yuan her family had paid for their flat was virtually all they had. 'That is all of my parents' and grandparents' savings. They have nothing else to live on,' she said. 'It took five generations to come up with that amount of money. We could never save up that much again in the rest of our lives.' Uniformed police surrounded the protesters and corralled them with patrol cars and vans as they made their way through the park to the municipal government's headquarters. About a dozen undercover police - complete with poorly concealed communications equipment - filmed and photographed individual protesters. Police repeatedly attempted to stop journalists photographing the protest, and initially tried to prevent protesters from speaking to the media.